Phyte Posted June 2, 2004 Share Posted June 2, 2004 I've got both heads. I'm using the stock pistons, so the N47 would make the compression too high right? I don't want to be limited on boost because my comp ratio is too high. Phyte Quote Link to comment Share on other sites More sharing options...
Phyte Posted June 2, 2004 Author Share Posted June 2, 2004 BTW I searched and I found one big debate but it was all about N/A engines. Phyte Quote Link to comment Share on other sites More sharing options...
technicalninja Posted June 2, 2004 Share Posted June 2, 2004 I would not use any head which had port liners in a turbo application. The port liners can loosen with the heat changes that the port will undergo between boost and non-boost. Also any restriction in exhaust port does not assist turbo motor as it can a N/A. I would stay with the P90. Also the P series heads have a larger squish area which helps reduce detonation. The stock L28ET has to low a compression ratio IMO and I am building a flat top F54/P90 combination for my Challenge car. This set up should net me approx 8.5/1 with minor combustion chamber mods. A compromise is to use a N42 head which has smaller comb chambers that the P90 but it doesn't have the improved squish area. I would stay with the P90 and change pistons first. Rick Quote Link to comment Share on other sites More sharing options...
Phyte Posted June 3, 2004 Author Share Posted June 3, 2004 Ok P90a it is. Any other comments? Phyte Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted June 3, 2004 Share Posted June 3, 2004 P90 head has better shaped combustion chambers as well, a more modern 'heart' shape as opposed to the round shape of the N42/47. Supposedly the heart shaped chambers are better at getting the fuel and air mixed... better quench area or something (sorry I forgot the technical mumbo jumbo ) and are much more resistant to detonation... better for turbo. Quote Link to comment Share on other sites More sharing options...
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